Digitizing is usually taught as part of a GIS course, but you won't learn much about it from me. In truth, it is horribly tedious and should be avoided whenever possible. Can you scan the map instead? Can you beg, borrow or steal that digital data from someone else? If you need some digitizing done, buy whatever basic tablet you need and hire a chump to do the work. First, try to convince this person digitizing is fun. Once he or she figures out how boring it really is, then pay whatever hourly wage it takes to ensure accurate, conscientious work. You should check the accuracy of the digitizing work frequently as it is being done.

As scanning technologies improve, digitizing is becoming less important. It is often quicker and cheaper to color-scan a map, use color filters to separate out the elements you want, register it to real-world coordinates and then simply label the desired elements with a digitizing or editing utility. Digitizing will always be necessary for some manual editing of files, however, so you should develop some familiarity with digitizing tools.

v.digit is GRASS's principal vector digitizing utility. For a detailed of its capabilities, check the v.digit tutorial The GRASS Reference Manual's discussion of it is limited. Unfortunately, the GRASS implementation on Strauss does not support v.digit.

v.digit supports digitizing over a backdrop raster map (so-called "heads-up" digitizing with a mouse rather than a digitizing tablet); bulk-labeling of unlabeled lines or areas (v.to.rast only rasterizes labeled vector features and ignores unlabeled ones); easy editing of attribute labels and categories; etc. If you do have access to a GRASS installation supporting v.digit, it's not particularly difficult to figure out if you just experiment with it.

After making any changes to a vector map with v.digit, you should always run v.support to re-build the topology. v.support has two options: the build option re-creates the dig_plus file and locates attributes labels in the dig_att file; the edit option lets you edit the dig_cats file category values and labels.

r.digit is a simple raster digitizing utility which does work on Strauss. Use it to create lines, circles or areas, specifying a category and label for each. When quitting r.digit, specify a new file name (or overwrite an existing file). r.digit can be used for free-hand editing of existing maps. Digitize the edits into a new file, then use r.mapcalc to paste them into the original map.

Since v.digit is not operational on Strauss, in a pinch you can raster digitize with r.digit, then use r.line or r.poly to vectorize the features.

d.rast.edit performs interactive pixel-by-pixel editing of cell values from a currently displayed raster map, writing these to a new map. (It doesn't modify the original map.) The resolution in the current region must match the current map's resolution. The program uses d.rast.zoom for zooming in and out, and d.rast.num for displaying cell values. Cell values cannot be changed to any value outside the current range of values in the map.